I'm a geochemist. In the past ten years I've fixed mass spectrometers, blasted sapphires with a laser beam, explored for uranium in a nature reserve, and measured growth patterns in fish ears, and helped design the next generation of the world's most advanced ion probe. My main interest is in-situ mass spectrometry, but I have a soft spot in my heart for thermodynamics, drillers, and cosmochemistry.

Sunday, January 17, 2016

When sand dunes, glac'ers spread across the farm
Migration to a sanctuary's best.
We need an Eden, Oregon lest harm
Befall environments which are distressed.
Six hundred fifty million years ago
The glac'ers covered every continent
Yet benthic evolution did not slow.
How'd life the frozen ocean circumvent?
A diamictite sandwich of black shale
With fossil seaweed as the veg'table.
In open water haven, they prevail
Suggesting snowball Earth was just a fable.
This promised land of cryogenic times.
Requires small, locally mild climes.

4 comments:

Snowball Earth pre-dates the Cambrian. Surely animal and bacterial life could have survived just fine around hydrothermal vents, even under ice?

Obviously, oxygen-fixing organisms existed both before and after the alleged snowball, and presumably would have needed sunlight. But algae can live on glaciers. There wouldn't have been dust to provide minerals, but there would have been volcanoes.

This paper presents evidence of multicellular algae-type plants in the middle of the glaciation. I don't see a major problem with a lineage going back and forth from multicellular to single-celled as conditions required.

The point is that the fossils show the continual evolution of large photosynthetic organisms, which are assumed to have lived somewhere close to the surface in open water. Can you get the full text, or are you stuck with abstract only?

If the fossils are detailed enough to show continual evolution of large photosynthetic organisms, then I retract my point. If they just show scattered points in a continuous lineage, then it seems plausible that a single lineage could go large, evolve for a while, leave fossils, go single-celled as conditions required, then go multi-celled again when the water opened up... lather, rinse, repeat.

Disclaimer:

All opinions, measurements, figures, and facts on this page are the personal opinions of Charles W. Magee, Jr, and do not represent the views of any of his employers: past, present, present-but-about-to-be-past, or future. None of the content herein has been subject to peer review, and should be treated with caution or derision. Any passing mention of OSHA code violations, criminal activities, unethical or unscientific behavior, or the clandestine Australian nuclear weapons program are fictions created to make rhetorical points, and do not represent the reality of my, or anyone else's, workplace. Do not attempt any scientific protocols described herein at home, with the exception of the chocolate chip cookie recipe. Do not apply the products of that protocol to individuals with heart disease, diabetes, high blood pressure or cholesterol, egg, wheat, dairy, or chocolate allergies. Do not view this blog continuously for more than 45 minutes without stretching and taking other precautions to prevent computer-related chronic injury.

As far as European privacy is concerned, Google (the blogger host) probably scrapes all sorts of data about you, but I don't really have access to what they take or how they use it, so ask them.